Method for flocking



-Oct. 7, 1941.

R. E. FOGG 2,258,092

METHOD FOR FLOCKING Filed Nov. 15, 1937 3 Sheets-Sheet l INVENTOR I'RnlpRT F ATTORNEY Oct. 7, 1941. R,

' METHOD FOR FLOCKING FOGG Filed Nov. 15, 1937 5 Sheets-Sheet 2 INVENTOR'ROEERT E,OGC. BY

ATTORNEY Oct. 7, 1941. R. E. FOGG METHOD FOR FLOCKING Filed NOV. 15,1957 3 Sheets-Sheet 3 I INVENTOR 'Rauu E F g 7-0 DRIER ATTORNEY PatentedOct. 7, 1941 UNITED STATES PATENT OFFICE nmrnon izz r iocxma Robert E.Fogg, Cambridge, Mass.

Application November 15, 1937, Serial No. 174,560

2 Claims.

The invention relates to methods of coating or flocking adhesive treatedpaper, fabric or other I accomplish these objects in the manner here-"inafter described and illustrated in the accompanying drawings in which:

Fig. 1'is a side levation, partly in section, showing apparatus which Ipreferably employ in practicing the methods of this invention for batchflocking, such as the flocking of groups of greeting cards;

Fig. 2 is a plan view of a vibrator plate and top plate for theapparatus shown in Fig. 1;

Fig. 3 is a side elevation, partly in section, of a modification of theapparatus shown in Fig. 1 adapted for use according to the presentinvention for continuous flocking of long strips or sheets of materials;

Fig. 4 is a section view of a modified form of vibration apparatus andmagnets for use in connection with the invention;

' Fig. 5 is an enlarged view of a fiat surface coatedwith flock inaccordance with the present invention, showing arrangement of thefibres.

Heretofore, the customary method of flocking has been to sift or dumpquantities of flock on the adhesiv treated surface of the material andsubsequently to subject the material to vibration in a direction normalto the treated surface to assure bonding of the fiock with the adhesive.

' When fiock is applied to the 'material in this fashion it collects onthe adhesive surface as a tangled mat with most of the fibres lying flaton the adhesive and is bonded with the adhesive of a continuous showerfrom above the vibrating surface. The fibres, even though very'light,tend to fall in endwise relation onto the surface, particularly if theyare more or less vertically arranged with respect to the surface at thestart of the fall, as may be assured by sifting the fiock onto thematerial through a screen of finer mesh in this form by th subsequentvibration. The

are uniformly driven endwiseinto th adhesive,

thus producing a smooth, deep coat of flock which has much theappearance of a nap.

I have discovered that a coat of flock in which than the length of thefibres. The fibres reaching the vibrating surface in endwise relationare driven into the adhesive in that position by the force of thevibration, without which the fibres would fall over and lie lengthwiseon the adhesive, the force of the fall alone, due to the lightness ofthe fibres, being insuflicient to cause vertical penetration into theadhesive. The vibration of the material being flocked is preferablyuniform throughout the area under treatment to assure uniformity of thecoat.

Flocking by this method attains a much superior coat of fiock to thatattained by prior methods in that a majority of the fibres are securedin upstanding endwise relation to the surface.

I have discovered, however, that in cases where rayon or silk fibreflock is used, this desirable effect can be further enhanced to thepoint of uniformity in vertical arrangement of the flock by subjectingthe falling fibres to theinfluence of a magnetic field, the lines offorce of which extend from below the vibrating material through andapproximately vertically thereto. I

have found that under the influence of such a magnetic field these flockfibres uniformly as-V sume and maintain a vertical position as respectsthe material surface while they contact it and are being driven by thevibration into the adhesive and I therefore believe that such fiockfibres must carry a charge and become polarized under the influence ofthe magnetic field, the fibre'end having a charge corresponding to thatof the magnet being attracted and the opposite end repulsed by themagnet.

My preferred method, therefore, consists in supplying flock in acontinuous shower to a vibrating adhesive treated surface and,particularly where rayon or silk fiock is used, maintaining magneticlines of force through and vertically of said surface. It will beunderstood, however, that use of the method of suppLving flock to thematerial as a continuous shower during light material vibration, withoutthe use of the magnetic field, produces a flock coat superior in pointof vertical arrangement of the flock to that obtainable by previouslyknown methods, although, in the case of rayon or silk flock at least,without the uniformity of such arrangement attainable with the aid ofthe magnetic field.

'In order. to assure uniformity in bonding of the flock with theadhesive on the materiaL. I prefer that all flock coated areas of saidmaterial be subjected to a uniform amount of vibration and that thematerial area exposed to the attached to the support. Conveniently, thesupport may-be a flat plate which is at least coextensive in area withthe material area exposed to the flock shower at any time.

In carrying out the methods of my invention, I prefer to employapparatus of the type illustrated in Figs. 1 and 3, in whichelectro-magnetic vibrators are employed to vibrate a rigid materialsupporting plate, both because the uniform vibration of material therebyattainable is particularly advantageous to obtaining a uniform coat offlock uniformly bonded and because I have found that the coils of suchvibrators produce a magnetic field through the material sufficient forpurposes of positioning flock, as previously described.

The apparatus shown in Fig. 1, which is fully described in my co-pendingapplication previously referred to; is arranged for batch flocking ofsmall area materials. It consists of table I, which has secured to itstop portion two electro-magnetic vibrators 2 comprising an armature 3and a coil 4, the latter connected to an electric current source.Secured .to the tops of the armatures, preferably throughan elasticconnecting medium, such as rubber supports 5, to increase the throw, isa lightweight, rigid vibrator plate the box is slid beneath it. Ifdesired, the outside end of the box may be provided with a subtionchamber l4, opening downwardly. through which excess flock may be drawnup from the plate 8, as the box I0 is moved across it, through .the tubeI! to a blower II which returns the flock to the hopper through tube II.

In use, the adhesive treated material is arranged and clamped on theplate I with the adhesive treated portions exposed, the box It, providedwith a layer of flock over the screen II, is moved to the position shownin Fig. 1 and the vibrators connected to current. The resultantvibration of the plate creates currents of air up and down through thescreen sufficient to produce the desired continuous shower of flockthrough the screen, thus obviating need for apparatus to shake thescreen. As previously explained, the majority of the fibres aremaintained in vertical position with respect to the plate I by theinfluence of the fall through the screen II and are thus firmly drivenendwise into the adhesive by the force of the vibration to form a flockcoat in which most of the flock particles -.are vertically disposed withrespect to the surface. In the case of rayon or silk flock, the furtherinfluence of the magnetic force exerted through the plate I by the coilsl of the vibrators produces a coat of flock such as shown in Fig. 5 inwhich the flock fibres are uniformly bonded in endwise relation "to thesurface 5|.

The apparatus shown in Fig. 3 represents a modification of that shown.in Fig. 1 for practice of the methods of the present invention inconnection with continuous flocking of large area flexible materials,such as the fabric II. In this vcase the vibrator apparatus 'is.slmilarto that shown in Fig. 1 except that the suction clampin system has beendispensed with, the fabric bei to which the adhesive treated material isclamped. To provide a suitable clamp for thin,

s, the plate 6 may be made hollow with small perforations in its upper;surface, as in Fig. 2, the cavity therein communicating with a. suitablesuction pump (not shown) through a tube 1. The materials to be flockedmay be placed on the apertured top of the plate I and secured thereto-bythe suction alone-or in addition, by a top plate 8 having apertures ofsuch size and arrangement as to expose all adhesive treated areas of thematerial.

The vibrator plate 8 extends upwardlyinto a trough O in which isslidably mounted a flock sifting box I I across which extends a flatscreen .Il, having a mesh somewhat smaller thanthe length of the flockused, such as a mesh screen. The trough I has cross pieces I! on whichthe ends of the box ll rest when it is in position over the vibrator asshown in Fig. 1, the box I I. together with the cross and side'pieces ofthe trough 8 thus forming a vertical closure around the plate 6. Theplate- 8 is preferably connected at its edges by flexible strips tothese cross aridsidepiecesofthe trough. Flock may be supplied throughthe open topfof the-box I. to the top of the screen "from a supplyhopper I 18 as" -ing maintained againstthe vibrator plate 8 bytension.The vibrator' plate I extends into-a vertical closure formed by sidestrips I 9 and cross strips 20 and II which may, in this case, besufiiciently' high to form the sides of the flock box I l. The screen Hin this'case is preferably of somewhat coarser mesh, such as a 30 mesh,for

reasons subsequently disclosed. The flock supply hopper i3 is mountedover the open top of box "and is shown as provided with a hand feedlever 22, although automatic feed mechanism such as a sired.

The cross strips ill and II have transverse slots II and 3-4 extendingsubstantially the length of the strips, the bottoms of said slotsslightly below the top of the plate 6 in its lbwermost position, and theslots having a depth somewhat greater than the length of the vibratingstroke of the plate 0, so that' the adhesive or flock coated fabric willnot touch the top of the slots as it approaches the vibrating plate 0through the slot 23 and leaves it through the slot 24. A

suction chamber 2' may be provided on the outside of the strip 2! havingits mouth flush with the top of the slot 24, for removing excess flockfrom the fabric.

The fabric a is drawn under a roll I'Lover roll ll, under adhesivedistributing nozzle 29 of adhesive tank 30. througha spreading'knife II,

through the slot Hover the plate I, through the,

slot 24, over rolls 3! and 33, and into a suitable v drying compartment(not shown).

The fabric I I is vibrated as it passes over the plate c, being heldagainst the plate I by the tension. The movementof air created in the IIby the vibratingv fabric andpiate slits thee-flock worm feed may beemployed if dewith. In Fig. 4 I have shown a.

aesaoes down through the screen H. The vertical movement of air,however, is not so great as in the apparatus shown in Fig. 1 due to thelateral openings 23 and 24, and, therefore, I have found that screen isadvisable to use of a somewhat coarser assure a sufficient shower offlock. The fabric is flocked by the vibration of the plate 6 as itpasses thereover, the flock flbresor particles being maintained invertical position under the combined influence of the sifting, fall,magnetic field and vibration as in the case of the apparatus shown inFig. 1.

While I prefer created by vibration to sift the flock as previouslydescribed, mechanical sifting means, such as a rotary screen,. may besubstituted for 'the flat screen ll if desired. v

The vibrator apparatus shown in Figs. 1 and- 3 is a preferredconstruction for the practice of methods of thi invention, .but othertypes of vibrators may a so be used in connection therevibrator of thebeater type ,which may, if desired, be substituted for the vibratorspreviously described, although with less eiilcient results. The vibratorof Fig. 4 comprises a rotatable-beater or paddle wheel 34 and a flexibletop piece 35, such as a tightly stretched piece ofcanvas. The bladescontacting the under surface of the top piece 35 in the manner showncause vibration of the top piece 35 and material secured thereto forflocking. Electromagnets 36 may be placed at either side of the beater34 to provide a magnetic field such as is present in the case of theelectro-magnetic vibrators.

Due to the flexibility of the top piece 35 and the fact that its "motionis not controlled with to make use of the air-currents ent invention inconjunction with this type of vibrator does not produce the uniformityin arrangementand bonding of the flock attainable when vibrators of thetype previously described are employed.

Having thus described the product and methods of my invention andapparatus for use in practicing the methods and producing the product,what I claim is:

l. A continuous method of coating a flexible sheet material with flockparticles which comprises applying adhesive to a surface of flexiblematerial, passing said material continuously through a flocking zone,tensioning said material in said zone upon the upper surface of a rigidhorizontally disposed plate, continuously showering flock downwardlyupon the adhesive treated surface of the material on the plate andsimultaneously continuously vibrating the plate rapidly vertically at aspeed and to an extent sufficient to embed the flock substantiallyuniformly in the adhesive on said material.

f respect to that of the beater, the vibration produced by this devicevaries in extent over the 2. A continuous methodof coating a flexiblesheet material with flock which comprises applying adhesive to a surfaceof flexible material, passing said material continuously through aflocking zone, tensioning said material in said zone upon the uppersurface of a rigid horizontally disposed plate, continuously showeringflock downwardly upon the adhesive treated surface of the material onthe plate and simultaneously continuously vibrating the plate rapidlyvertically at a speed and to an extent suillcient to embed the flocksubstantially uniformly in the adhesive on said material and creatingbeneath the vibrating material a magnetic field which polarizes theflock particles falling onto said surface of the material and positionsthem endwise relative 'to said surface.

i v ROBERT E. FOGG.

